Re: postgres_fdw insert extremely slow

On 25.11.2020 17:57, Adrian Klaver wrote:
> On 11/25/20 8:48 AM, Mats Julian Olsen wrote:
>> Apologies for the sloppiness!
>>> Postgres version(s)?
>>
>> x: Aurora PostgreSQL 11.7 on x86_64-pc-linux-gnu, compiled by gcc 
>> (GCC) 4.9.3, 64-bit (RDS)
>>
>> y: PostgreSQL 12.2 (Ubuntu 12.2-2.pgdg19.10+1) on 
>> x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 9.2.1-9ubuntu2) 9.2.1 
>> 20191008, 64-bit (GCP)
>
> So they are separated by what network distance?
>
By quite a lot! One server is in eu-west-1 and the other in gcp 
us-central1-a. Note however, that SELECTs across the network are very 
fast, so it doesn't seem like this is a network issue.
>>
>>>
>>> Without the actual query and EXPLAIN ANALYZE on it this will be 
>>> difficult to answer with any detail.
>>>
>>> Also would be nice to have the table schema.
>>>
>>
>> Here's the query, schema and the EXPLAIN ANALYZE
>
> FYI, you will get more responses by including below information 
> directly in the email. To that end:
>
> On x
>
> CREATE TABLE labels (
>     id integer NOT NULL,
>     address_id bytea NOT NULL,
>     name text NOT NULL,
>     author character varying(50) NOT NULL,
>     type text NOT NULL,
>     source text,
>     updated_at timestamp with time zone DEFAULT now() NOT NULL,
>     CONSTRAINT lowercase_name CHECK ((name = lower(name))),
>     CONSTRAINT lowercase_type CHECK ((type = lower(type))),
>     CONSTRAINT whitespace_name CHECK ((regexp_replace(btrim(name, ' 
> '::text), '(\s+)'::text, ' '::text, 'g'::text) = name)),
>     CONSTRAINT whitespace_type CHECK ((regexp_replace(btrim(type, ' 
> '::text), '(\s+)'::text, ' '::text, 'g'::text) = type))
> );
> CREATE INDEX labels_label ON labels USING BTREE (name);
> CREATE INDEX labels_label_type ON labels USING BTREE (type);
> CREATE INDEX labels_address ON labels USING HASH (address_id);
> CREATE INDEX labels_source ON labels USING BTREE (source);
>
> On y
>
> CREATE TABLE labels.labels (
>     address     bytea PRIMARY KEY,
>     labels      text[]
> );
>
>>
>> query: https://gist.github.com/mewwts/704663e19a21bc51864f3298f09a18c0
>
> INSERT INTO foreign.labels (address, labels)
> SELECT address_id, ARRAY_AGG(name) AS labels
> FROM labels
> GROUP BY 1
> LIMIT 100;
>
>>
>> plan: https://explain.depesz.com/s/RQFQ
>
> Insert on labels  (cost=0.42..26.19 rows=100 width=53) (actual 
> time=11541.205..11541.205 rows=0 loops=1)
>    ->  Limit  (cost=0.42..25.19 rows=100 width=53) (actual 
> time=0.068..3.549 rows=100 loops=1)
>          ->  GroupAggregate  (cost=0.42..26502.02 rows=106996 
> width=53) (actual time=0.066..3.449 rows=100 loops=1)
>                Group Key: labels_1.address_id
>                ->  Index Only Scan using 
> labels_address_id_type_name_key on labels labels_1 
> (cost=0.42..24068.85 rows=219145 width=31) (actual time=0.054..0.414 
> rows=201 loops=1)
>                      Heap Fetches: 0
>  Planning Time: 0.102 ms
>  Execution Time: 12797.143 ms
>
>
>>
>>
>> Best,
Thank you for inlining this!

-- 
Mats
CTO @ Dune Analytics
We're hiring: https://careers.duneanalytics.com